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Peter Anvin" , David Hildenbrand , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Pedro Falcato , Jarkko Sakkinen , Oscar Salvador , Kuninori Morimoto , Oven Liyang , Mark Rutland , Ada Couprie Diaz , Robin Murphy , Kristina =?utf-8?Q?Mart=C5=A1enko?= , Kevin Brodsky , Yeoreum Yun , Wentao Guan , Thorsten Blum , Steven Rostedt , Yunhui Cui , Nam Cao , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [RFC PATCH 0/2] mm: continue using per-VMA lock when retrying page faults after I/O Message-ID: References: <20251127011438.6918-1-21cnbao@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251127011438.6918-1-21cnbao@gmail.com> X-Stat-Signature: 8y9t88m7wy4u7phii169bb7b3xqbxja3 X-Rspam-User: X-Rspamd-Queue-Id: 12A90180007 X-Rspamd-Server: rspam09 X-HE-Tag: 1764216584-5294 X-HE-Meta: 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 UJJWa7cP O96R8XiO3l1NSFRwXUANF5Kb7ZTD3YCQsTvb7J/Pru8DHWQElAZuI4qIAmcPxks0JTXNK9uxTuWPJuCcL3TK4AHf5RLHoGX1P2VfyLFEbLrv1vc2rVqqnIWANNQRASVNa2lLEXMgzmrkv4SDzd5szgFhp2fDqR3dt/ZtSpOqagno7Xdjey5fxhvwmi5o1/hwiRJijI2j/9fZUNraq4sX+I/MMD0PKzQNSVI1typQ6V/a1+cyFcrXPgGHpBQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Nov 27, 2025 at 09:14:36AM +0800, Barry Song wrote: > There is no need to always fall back to mmap_lock if the per-VMA > lock was released only to wait for pagecache or swapcache to > become ready. Something I've been wondering about is removing all the "drop the MM locks while we wait for I/O" gunk. It's a nice amount of code removed: include/linux/pagemap.h | 8 +--- mm/filemap.c | 98 ++++++++++++------------------------------------- mm/internal.h | 21 ----------- mm/memory.c | 13 +------ mm/shmem.c | 6 --- 5 files changed, 27 insertions(+), 119 deletions(-) and I'm not sure we still need to do it with per-VMA locks. What I have here doesn't boot and I ran out of time to debug it.